Question

QUESTION 1

Which of the following statements regarding splicing is FALSE?

      

A) The length of introns determines the efficiency of splicing.

B) Many human neurological disorders are caused by splicing errors and/or mutations in splicing factors.

      

C) Splicing requires the action of a variety of snRNAs that direct the transesterification reactions.

      

D) Splicing is dictated by sequence features in pre-mRNA transcripts

QUESTION 2

Which of the following mRNA processing factors does NOT associate with the CTD of RNA polymerase II?

      

A) splicing factors

      

B) polyadenylation factors

      

C) miRNAs/siRNAs

      

D) capping proteins

QUESTION 3

Which of the following statements about mRNA stability is FALSE?

      

A) Deadenylation-independent mRNA decay is exclusively in the 5' to 3' direction.

      

B) The most common pathway of mRNA decay is deadenylation-dependent.

      

C) Yeast mRNA decay occurs primarily in the 5' to 3' direction, while 3' to 5' decay is more common in mammalian cells.

      

D) Decapping enzymes are required for all pathways of mRNA decay.

QUESTION 4

You obtain the sequence of a gene containing 10 exons, 9 introns, and a 3′ UTR containing a polyadenylation consensus sequence. The fifth exon also contains a polyadenylation site. To test whether both polyadenylation sites are used, you isolate mRNA and find a longer transcript from muscle tissue and a shorter transcript from all other tissues. Which of the following is the most likely mechanism underlying these alternative transcripts?

A) The fifth exon is spliced out of the mature mRNA transcript in muscle cells.

      

B) Muscle cells have less effective polyadenylation than other tissues.

      

C) An alternative CPSF protein is expressed in muscle cells with lower affinity for the polyadenylation sequence in exon 5.

      

D) The mRNA in muscle cells is edited to eliminate the polyadenylation sequence in exon 5.

Answer 1

Answer 1: The following statement is false:

D) Splicing is dictated by sequence features in pre-mRNA transcripts

As splicing is dictated by Splicosome machinary which does not need pre-mRNA transcripts.

Answer 2: The following statement is false:

C) miRNAs/siRNAs

As the above are involved in RNA interferance and not in splicing.

Answer 3: The following statement is false:

A) Deadenylation-independent mRNA decay is exclusively in the 5' to 3' direction.

As the deadenylation-independent mRNA decay is exclusively in the 3' to 5' direction.

Answer 4: The following statement is false:

B) Muscle cells have less effective polyadenylation than other tissues.

As the transcript obtained from muscle cells is longer compared to all the others due to the presence of multiple poladnylation sites.